Obstruction-operated microswitches are well known in the art for controlling machines as shown in:
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for controlling presses as shown in:
for controlling doors and gates as shown in:
for controlling feed mechanisms as shown in:
Also it is well known that to have mechanical, that is non-electrical, obstruction operators with levers, springs and slot structures as disclosed in:
Nevertheless, applicant's specific structure for the movable mounting of a reciprocating hydraulic motor in which the whole motor is movable when an obstruction is contacted in its downward movement path, was not known to applicant, particularly for the specific use as a safety feature for hydraulic lifts for wheelchairs mounted in vehicles, so that in lowering the lift no one could be seriously injured if they happened to be in the path of the downward movement of the lift platform.